Petersen SM, et al. - Researchers examined the risk of a substance abuse diagnosis in correlation to a diagnosis of schizophrenia. Using various Danish registers, they identified a cohort of 3,133,968 persons. Of these, 14,007 individuals developed schizophrenia, and 2,885 of them received a subsequent diagnosis of substance abuse during follow up (103,212,328 person-years at risk). Observations revealed a significant correlation of a diagnosis of schizophrenia with increased risk of a subsequent diagnosis of substance abuse. In Denmark, 10-15 years following a diagnosis of schizophrenia, the association was still significant.